Fuel cells have been used as a power source in many applications. For example, fuel cells have been proposed for use in electrical vehicular power plants to replace internal combustion engines. In proton exchange membrane (PEM) type fuel cells, hydrogen is supplied to the anode of the fuel cell and oxygen is supplied as the oxidant to the cathode. PEM fuel cells include a membrane electrode assembly (MEA) comprising a thin, proton transmissive, non-electrically conductive, solid polymer electrolyte membrane having the anode catalyst on the active area portion of one face and the cathode catalyst on the active area portion of the opposite face. The MEA is sandwiched between a pair of non-porous, electrically conductive elements or bipolar plates which serve as current collectors for the anode and cathode, and contain appropriate channels and/or openings formed therein for distributing the fuel cell's gaseous reactants over the surfaces of the respective anode and cathode catalysts.
The electrically conductive bipolar plates sandwiching the MEAs may contain an array of grooves in the faces thereof that define a reactant flow field for distributing the fuel cell's gaseous reactant's (i.e., hydrogen and oxygen in the form of air) over the surfaces of the respective cathode and anode. These reactant flow fields generally include a plurality of lands that define a plurality of flow channels therebetween through which the gaseous reactants flow from a supply header at one end of the flow channels to an exhaust header at the opposite end of the flow channels.
The portions of MEA faces beyond the active area are typically used as seal surfaces. On these edges of the membrane electrolyte, main gaskets or seals are disposed to peripherally frame the bipolar plates, preventing the membrane electrolyte from contacting the plates. Additional thin polymeric film gaskets have also been used between the membrane electrolyte and the diffusion media of the fuel cell. Due to significantly higher compression and shear stresses on the membrane electrolyte at the gasket interfaces during the stack build process, the sensitive membrane may fail prematurely. Thus there is a need for improved manufacture of these elements.